According to Click2Houston, Texas legislation that passed earlier this year and will negatively affect Hurricane Harvey victims will go into effect on September 1. Basically, House Bill 1774 reduces penalties to insurance companies when they don't pay out enough insurance claims. Earlier this year The Texas Tribune wrote:

... the bill would discourage property owners from suing insurers over weather-related claims.

The article explains that if victims file their claims by September 1, 2017, insurance companies will suffer an 18% penalty interest for slow or no payment. However if filed after September 1, 'insurers who deny or delay paying claims would only face a 10% penalty.'

I’ve been hearing that some insurance companies are telling people to wait a week until they have pictures of the damage before filing their claim. You do not need to attach pictures of your claim. You can always supplement with photos if need be.

Dallas News says in order to ensure your claim will be filed, a phone call or message will not suffice. You must email directly or send mail dated before September 1 to your insurance company. Even then it doesn't guarantee anything but it is the best chance for homeowners to protect themselves from the new policy that favors the company instead of policy holders.